"Once I found out the numbers were good, I immediately texted [star] Stephen [Amell] to say congratulations and job well done," Barrowman explained.

"Stephen was so excited, that he tweeted it before it was even announced. That gives you an idea of the feeling we have as the actors when it happens, we are happy about it and ecstatic that our story gets to be told."

The Arrow mid-season finale will air on Sky1 in the UK this Monday at 8pm. In the US, the series will return to The CW on January 16.